... tries to spin it, the friction between the gear and the worm holds the worm in place.This feature is ... Torsen differential, which is used on some high-performance cars and trucks. Material:carbon steel such as C45, 20CrMnTi, 40Cr, ... , grinding, broaching, thread rolling and so on. Heat Treatment: Hardening and Tempering, High Frequency Quenching, Carburizing Quenching and so on. Standard: European or ...